SQL Server BCP based load enhancements

[sm-shaw]

PR #587 has added BCP based loads to the TPROC-C schema for SQL Server that are at least 2X faster than the default insert based loads.
Potential further enhancements are:

1. Currently, SQL authentication is supported, adding the -T flag could also use Windows authentication and then BCP based loads could become the default.
2. BCP based loads could be added to the TPROC-H schema.
3. extending the tdbc::odbc interface to add the bcp_init, bind and sendrow commands and call these directly from ODBC rather than the external bcp command
   https://learn.microsoft.com/en-us/sql/relational-databases/native-client-odbc-extensions-bulk-copy-functions/bcp-init?view=sql-server-ver16
   https://learn.microsoft.com/en-us/sql/relational-databases/native-client-odbc-extensions-bulk-copy-functions/bcp-bind?view=sql-server-ver16
   https://learn.microsoft.com/en-us/sql/relational-databases/native-client-odbc-extensions-bulk-copy-functions/bcp-sendrow?view=sql-server-ver16